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Ecosystem Recovery from Disturbance is Constrained by N Cycle Openness, Vegetation-Soil N Distribution, Form of N Losses, and the Balance Between Vegetation and Soil-Microbial Processes
Ecosystems ( IF 3.7 ) Pub Date : 2020-08-17 , DOI: 10.1007/s10021-020-00542-3
Edward B. Rastetter , George W. Kling , Gaius R. Shaver , Byron C. Crump , Laura Gough , Kevin L. Griffin

We present a framework for assessing biogeochemical recovery of terrestrial ecosystems from disturbance. We identify three recovery phases. In Phase 1, nitrogen is redistributed from soil organic matter to vegetation, but the ecosystem continues to lose nitrogen because the recovering vegetation cannot take up nitrogen as fast as it is released from soil. In Phase 2, the ecosystem begins re-accumulating nitrogen and converges on a quasi-steady state in which vegetation and soil-microbial processes are in balance. In Phase 3, vegetation and soil-microbial processes remain in balance and the ecosystem slowly re-accumulates the remaining nitrogen. Phase 3 follows a balanced-accumulation trajectory along a continuum of quasi-steady states that approaches the true steady state asymptotically. We examine the effects of three ecosystem properties on recovery: openness of the nitrogen cycle, nitrogen distribution in and turnover between vegetation and soils, and the proportion of nitrogen losses that are in a refractory form. Openness exacerbates Phase 1 nitrogen losses but speeds recovery in Phases 2 and 3. A high fraction of ecosystem nitrogen in vegetation, resulting from nitrogen turnover that is slow in vegetation but fast in soil, exacerbates Phase 1 nitrogen losses but speeds recovery in Phases 2 and 3. A high proportion of nitrogen loss in refractory form mitigates Phase 1 nitrogen losses and speeds recovery in Phases 2 and 3. Application of our conceptual framework requires empirical recognition of the continuum of quasi-steady states constituting the balanced-accumulation trajectory and a distinction between the balanced-accumulation trajectory and the true steady state.



中文翻译:

氮素循环开放度,植被-土壤氮素分布,氮素损失形式以及植被与土壤-微生物过程之间的平衡限制了生态系统从干扰中恢复

我们提出了一个框架,用于评估来自干扰的陆地生态系统的生物地球化学恢复。我们确定了三个恢复阶段。在阶段1中,氮从土壤有机质重新分配到植被,但是生态系统继续损失氮,因为恢复的植被吸收氮的速度不能像从土壤中释放的氮那样快。在阶段2中,生态系统开始重新积累氮,并收敛于植被和土壤微生物过程处于平衡状态的准稳态。在第三阶段,植被和土壤微生物过程保持平衡,生态系统缓慢地重新积累剩余的氮。阶段3沿着平衡稳态的轨迹,沿着一个连续的准稳态逐渐渐进地接近真实稳态。我们研究了三种生态系统特性对恢复的影响:氮循环的开放性,氮素在植物和土壤之间的分布以及氮素在土壤和土壤之间的周转以及氮素以耐火形式流失的比例。开放性加剧了阶段1的氮损失,但加快了阶段2和3的恢复。植被中缓慢但土壤快速的氮周转导致植被中较高的生态系统氮含量,加剧了阶段1的氮损失,但加快了阶段2和3的恢复。 3.高比例的耐火形式氮损失减少了阶段1的氮损失,并加快了阶段2和3的恢复。

更新日期:2020-08-17
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